One type of well known juice extractor includes a series of juice extractor units that are ganged together. Each juice extractor unit includes upper and lower cups for supporting the fruit. The sides of both upper and lower cups have fingers that intermesh or interdigitate together. The upper cups are mounted on a common cross bar, which moves in a fixed up and down path by means of a cam-drive positioned at the top of the juice extractor machine. The upper cups move into the bottom cups, which remain rigidly positioned.
A fruit, such as an orange, is initially fed into the bottom cup by a cam-operated feeding device, which deposits the fruit in the bottom cup. The upper cup then descends into the lower cup. The fruit is pressed against sharp circular cutters positioned at the top of a strainer tube adjacent the lower cup, and an upper cutter positioned in the upper cup. The two circular cutters cut plugs into both the top and bottom portions of the fruit as the interdigitating fingers of the two cups mesh together. At the same time, the inner portions of the fruit (i.e., the pulp and juice) are forced down into the strainer tube positioned within a manifold. The peeled surfaces of the fruit do not contact the juice as the interdigitating fingers peel the fruit. After the upper cup has descended toward the lower cup, an orifice tube moves upward into the strainer tube. The orifice tube includes a restrictor in its lower end. The orifice tube applies pressure into the internal portion of the strainer tube to separate juice and pulp within the strainer tube, collect the core material and discharge the core material out of the bottom of the orifice tube. The core material typically includes membrane, seeds and peel plugs.
Each of the upper and lower cups, together with the strainer tube and orifice tube, form a single juice extractor unit. Typically, three or more juice extractor units are ganged together to increase production and are positioned in one housing. The orifice tubes may include a mounting assembly that is ganged together, such as by a drive beam that supports each of the mounting assemblies and is moveable to reciprocate the orifice tubes within the strainer tube.
The orifice tube must be designed such that it has free movement with in the strainer tube. During normal operation of the juice extractor, this movement is restricted only by the force needed to compress the core material into the orifice tube restrictor area and force the juice through the strainer tube holes. Typically, this force has been measured and is about in the range of 200 to 1,000 psi.
There are also times when an opposing force to the upward movement of the orifice tube can exceed the pressure. This can occur such as when foreign material stops upward movement of the orifice tube, and, as a result, the orifice tube becomes lodged within the strainer tube. This foreign material can include a twig, golf ball, aluminum foil or any other type of foreign material. When this occurs, the juice extractor can be damaged, including the orifice tube, and different drive components, including orifice tube drive beam, pull rods, cam follower bearings, cam followers, alignment assemblies, and the strainer tube. Besides the mechanical damage that can occur, the operational down time required the necessary repairs is also very expensive and can require considerable labor to repair, which also is expensive.
Additionally, the orifice tube could seize within the strainer tube on the downward travel, such as when there is no fruit juice to provide lubrication. Sometimes the orifice tube gets very hot because there is no fruit acting as a lubricant. Additionally, some cleansing solutions may become very hot and the orifice tube could expand and seize within the strainer tube.